We purchased this tank because we are on a gravity feed from the well tank with low pressure. We've been pleased with the ease of installation hook-up and functionality. You have to play with the settings to dial in the water to heat ratio for perfect performance.
Advantages: Works with low flow water supply. Heats the water well during the summer. In fact it can be too hot so have good expectations for this winter's hot water supply as well.
Disadvantages: We have a minimal system in our off grid shack. This unit is easily able to handle our demands. I think it would be overwhelmed using it alone in a large house.